> > I thought it was because there was little to no documents for the GPUs/CPUs > > ElSemi and Olivier Galibert figured it out pretty well. It's just that ElSemi's code> is heavily tied to x86 32-bit (you'll notice there isn't a 64-bit version of his> emulator, and forget about an ARM port) and thus it doesn't really drop into MAME in> any meaningful way. Also, the fact that his emulator exists makes it less interesting> to get it right in MAME.

At least until x86/Win32 code becomes largely obsolete... Once mainstream operating systems make the move to 64-bit only with no 32-bit variants, this will be the main turning point and there will be no choice but to convert everything or cease production (in a companies' point of view).

In reality, the transition from 32-bit to 64-bit is just the Win3.x to Win95 movement all over again - 16-bit programs ceased to exist whilst companies released later program versions as 32-bit only (complete with the Designed for Windows 95 logo on the packaging), making their software no longer compatible with Windows 3.x and forcing users to either upgrade their systems or be stuck with obsolete technology.